The invention relates to a high voltage distribution substation that is hybrid, i.e. comprising both busbars and feeders using air-insulated technology, and also metal-clad break and switch modules comprising break and disconnector devices in metal cladding, the modules being used for interconnecting the busbars and the feeders.
As a preliminary point, it is worth enlarging on the concept of a xe2x80x9chybridxe2x80x9d high voltage substation since it is relatively recent. Air insulated technology is referred by the initials AIS (for air insulated system) and metal-clad technology by the initials GIS (for gas insulated system). The main desired objective is to reduce the ground area occupied by conventional substations (i.e. fully AIS substations), while nevertheless conserving both the advantages of AIS technology in terms of cost and ease of component replacement, and the advantages of GIS technology in terms of compactness and behavior relative to pollution. Hybrid substations can be installed as new facilities, but also as extensions to a conventional substation where the space available for an extension is limited.
A conventional substation having two sets of opposite busbars and feeders is shown in FIGS. 1, 1a, and 2. That type of substation occupies a large area on the ground firstly in the direction of the feeder bays (i.e. lengthwise) and secondly in the direction of the busbars (i.e. widthwise) because the feeders need to be opposite in offset bays. The switchgear belonging to a particular feeder must be located beneath both sets of busbars.
In order specifically to reduce the length of conventional substations, hybrid high voltage substations of the kinds shown diagrammatically in FIGS. 3 and 6 have been developed that use metal-clad breaking and switching modules for interconnecting the busbars and the feeders. Such known metal-clad modules are known, in particular from PCT application WO 00/24100 in which FIGS. 1 and 2 show single-phase modules for substations having single and double sets of busbars. In that technology, each feeder is associated with its own module, each module serving to connect one or two sets of busbars to a feeder. Thus, two opposite feeders use two modules and are necessarily located in two bays that are offset when the substation has more than one set of busbars. Compared with a conventional substation, that type of hybrid substation makes it possible to reduce the length of feeders, and thus the length of the substation, but does not make it possible to achieve any significant increase in the number of bays that can be installed in a given area. Furthermore, that technology does not make it possible to interconnect two opposite feeders directly when a module needs to be disconnected from a set of busbars due to an incident thereon.
The Applicant has devised a novel type of metal-clad module for making hybrid substations with facing opposite feeders, enabling manufacturing costs to be reduced and also making it possible to achieve a significant increase in the number of bays that can be installed in a given area compared with existing substations. A hybrid substation of the invention also makes it possible, if necessary, to perform a function of electrical connection between two opposite feeders.
To this end, the invention provides a xe2x80x9chybridxe2x80x9d high voltage multiphase distribution substation having one or more sets of busbars including at least one air-insulated set of busbars, the substation having feeders for air-insulated lines placed in substantially parallel bays on either side of the set(s) of busbars and including metal-clad breaking and switching modules each formed by metal cladding containing, for each electrical phase passing through a module, breaking and disconnection systems connected to a phase conductor in an insulating gas, an end disconnection system being placed at each of the two ends of a module, the substation being characterized in that the feeders are opposite in facing pairs, and in that two opposite feeders are electrically interconnected for each electrical phase via a single module when the break systems and the end disconnector systems of said module are closed, said end disconnector systems each being connected to a respective feeder.
In an embodiment of the invention, a single multiphase module electrically interconnects two opposite feeders. For example, for a three-phase substation, two opposite feeders are interconnected by a three-phase module having three phase conductors passing therethrough contained inside the metal cladding of said module and each connected to a respective overhead bushing at each end of the module.
In an embodiment of the invention, two opposite feeders of a substation convey a number n of electrical phases and are interconnected by n single-phase modules. For example, for a three-phase substation, two opposite feeders are interconnected by three single-phase modules each having a single-phase conductor passing therethrough and connected to an overhead bushing at each end.
In a preferred embodiment of the invention, the first and second feeders form aligned bays that are perpendicular to a set of busbars. For a substation having at least two sets of busbars, the two sets are generally parallel to each other and perpendicular to the feeders.
In an embodiment of the invention, each end disconnector system in the cladding of a module comprises, for each electrical phase, an end disconnector leading to an overhead bushing electrically connected to a feeder of the substation, and in which said end disconnectors are connected in series with two break systems comprising two circuit breakers themselves disposed on either side of one or two incoming disconnectors each leading to an overhead bushing electrically connected to a corresponding busbar of a set of busbars. The embodiment having a single incoming disconnector is particularly intended for installing the module in a substation having a single set of busbars where the incoming disconnector is generally referred to as the busbar disconnector.
In an embodiment of the invention, the substation has two sets of busbars and a breaking and switching module has two incoming disconnectors directly connected to each other by the phase conductor. The two incoming disconnectors are generally referred to as switching disconnectors.
In an embodiment of the invention, the substation has two sets of busbars and a breaking and switching module has two incoming disconnectors connected to each other by a separation disconnector in series with the phase conductor.
The invention also provides a breaking and switching module formed by metal cladding containing an insulating gas, and for each electrical phase: a first circuit breaker connected to a phase conductor passing through said module; each of the two ends of said module having an end disconnector per phase connected to an overhead bushing; an incoming disconnector being located between the circuit breaker and one of the end disconnectors; the module being characterized in that the cladding contains a second circuit breaker connected in series with the first circuit breaker in such a manner that the incoming disconnector is situated between the first and second circuit breakers. This type of module of the invention is intended in particular for hybrid substations having a single set of busbars and for H hybrid substations. The incoming disconnector of a module of the invention is generally referred to as the busbar disconnector. In most applications, it leads to an overhead bay, but it is also possible to have it lead to a box for sheathed cables or to a metal-clad line without going the ambit of the invention.
In an embodiment of the invention, the cladding of a module contains for each electrical phase a second incoming disconnector placed between the first and second circuit breakers. This embodiment is particularly intended for installing the module in a substation with two sets of busbars where the two incoming disconnectors are generally referred to as switching disconnectors. In a first embodiment of a module, the two incoming disconnectors are directly interconnected by the phase conductor. In a second embodiment, a separator disconnector in series with the phase conductor interconnects the two incoming disconnectors so as to make it possible to isolate the two symmetrical halves of the module from each other. The two sets of busbars in a substation of the invention can be entirely air-insulated (AIS) or it can comprise a combination of AIS and GIS, with a first set of busbars in air and a second set in metal cladding.
In another embodiment of a hybrid substation module of the invention, in particular intended for a xe2x80x9cone-and-a-half breakerxe2x80x9d configuration, two feeders and two sets of busbars are interconnected by a module comprising three circuit breakers in series, one circuit breaker being placed between the two disconnectors which are used as outgoing disconnectors leading to line feeders. Other substations of the xe2x80x9cone-and-a-half breakerxe2x80x9d type can be implemented by associating a two circuit breaker module of the invention with a conventional module having a single circuit breaker.
Optionally, at least one break or disconnection system for a module of the invention is placed in a compartment specific thereto within the cladding of the module, said compartment being isolated in leakproof manner from the adjacent compartments.
Optionally, a module of the invention has at least one current transformer disposed between an end disconnector and an overhead bay, and/or between an incoming disconnector and a circuit breaker.